I still can't find any dynos for sale... anywhere. Are there any write ups of people making their own? Since I have a lathe and mill, im no stranger to metal work... its just the electronics side I'm not sure about. A flywheel is a good idea if I could accurately time it and log rpms. I can't see why such a system would be strictly for brushed or brushless motors.

I have recently acquired a suitable flywheel, and I now need to make a mounting system to hold everything.

I can provide you with the electronics if you can make the flywheel and mount. PM me if you are interested.

In theory, a flywheel dyno can be used on any motor, brushed or brushless. The problems for any particular system lie only in the execution. The Robitronics flywheel is too light for our 540-size brushless motors, giving insufficient data. Also, my dyno uses the motor's Hall sensors to gather the data, and these (of course) don't exist on a brushed motor.

To get accurate timing data, it is imperative to have a direct connection between flywheel and motor. A gear or belt drive has far too much lash, play, and flexibility to get the accuracy I desire. In addition, the time measurement must have resolution on the order of a few microseconds to get the accuracy I desire, and commercially-available systems fall far short of this.